RALEIGH, N.C. (AP)  The U.S. government is working to extradite a former Salvadoran colonel to face charges that he helped plot the 1989 slayings of five Jesuit priests from Spain during El Salvador’s civil war, prosecutors said Wednesday.

Inocente Orlando Montano Morales, 72, is one of 20 former military officials who were indicted in Spain on charges related to the notorious killings known as the Jesuit Massacre, according to a news release from the U.S. Department of Justice.

A federal prosecutor in North Carolina, where Montano Morales is serving a prison sentence for immigration fraud, filed a complaint Wednesday in federal court seeking to extradite him to Spain.

A lawyer who worked with the victims’ families to pursue the criminal case said the prosecution of Montano Morales will be significant because the rest of the accused officers aren’t likely to be extradited from El Salvador.

“His case will be the site where the full truth of what happened that night and the role that high level military officials played in the crime will be prosecuted,” said Carolyn Patty Blum, senior legal adviser to the Center for Justice & Accountability.

From 1980 to 1991, El Salvador was caught in a conflict between the government and leftist rebels, and the priests had been calling for discussions between the two sides to end the fighting, according to court documents.

The complaint says Montano Morales, who also served as El Salvador’s vice minister of defense and public safety, oversaw a government radio station that issued death threats against Father Ignacio Ellacuria Beascoechea and other priests. It says the colonel was present during a meeting when another officer “gave the order to kill Father Ellacuria and leave no witnesses.”

The following day, Nov. 16, 1989, members of the Salvadoran military killed six Jesuit priests, their housekeeper and the housekeeper’s 16-year-old daughter, court documents say. Five of the priests were from Spain, while the rest of the victims were from El Salvador.

A translated arrest warrant issued in Spain states that Montano Morales is accused of murder and other charges.

Montano Morales is serving a 21-month federal prison sentence for immigration fraud and perjury, and his sentence at a North Carolina prison was set to finish later this month.

The former colonel has denied involvement in the killings of the priests. A message left seeking comment from his lawyer in the immigration case wasn’t immediately returned.

He told a judge in 2011 that he’d come to the U.S. about 10 years before his 2011 arrest. He’d been living in the Boston suburb of Everett and worked for six years in a candy factory, making $14 an hour.

A 2011 affidavit filed by an investigator said Montano Morales falsely claimed he hadn’t served in the military on an immigration form for people seeking temporary immigration status because they can’t safely return to certain countries.

Blum said her organization partnered with a Spanish advocacy group to file a 2008 complaint asking authorities there to look into the case. The indictments were issued in 2011 after an investigation by a Spanish court.

Of the others indicted, one has died and the other 18 are in El Salvador, Blum said. She says a Salvadoran law granting amnesty to people who participated in the conflict is preventing their extradition.

“As it stands now, those defendants are not going to be extradited to Spain,” she said.